1. Field of the Invention
This invention relates to bearing seals between a housing and a rotatable shaft. In one of its aspects, the invention relates to a bearing seal for use between a steering column and the body of an automobile.
2. State of the Prior Art
A seal structure between a steering shaft and an automobile body should seal the inside from the outside and permit rotation of the steering column about its longitudinal axis. Further, the bending stresses on the steering column should be minimized. The bending stresses on the steering column can result from manufacturing tolerances or slight errors in lining up the two support bearings for the shaft in the automobile body. Thus, ideally, the bearings will have some flexibility for alignment purposes and provide a seal, preferably thermal as well as dirt, air, moisture and noise, and permit relatively frictionless rotation of the steering shaft with respect to the automotive body.
The U.S. patent to Shiomi et al 4,185,880, issued Jan. 29, 1980, discloses a steering column bearing wherein a ball bearing assembly is provided to permit rotation of the steering column with respect to the body and the ball bearing assembly itself is mounted in a spherical, concave surface to allow pivotable movement of the axis of the shaft about three axes of freedom.
This bearing assembly does not appear to provide a good thermal, dirt, noise, air and moisture seal without additional packing or boots and is more costly.
Bearing shaft seals including flexible sealing members for many other purposes have been devised. For example, Reich in U.S. Pat. No. 2,476,324, issued July 19, 1949, teaches a sealing assembly in which a pair of rubber rings having frusto-conical shaped sealing lips are held in a metal collar and a metallic plate. One of the sealing lips seals against the shaft but the shaft rotates or slides with respect to the sealing lip.
Shaft sealing bearings of relatively rigid nature are shown by the following U.S. Pat. Nos.:
Roschlau 2,704,230 (issued Mar. 15, 1955) PA0 Gunnell 3,086,826 (issued Apr. 23, 1963) PA0 Kume 4,133,587 (issued Jan. 9, 1979) PA0 Bosco 4,204,718 (issued May 27, 1980)